<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>jQuery UI 滑块（Slider） - 对齐增量</title>
  <link rel="stylesheet" href="//apps.bdimg.com/libs/jqueryui/1.10.4/css/jquery-ui.min.css">
  <script src="//apps.bdimg.com/libs/jquery/1.10.2/jquery.min.js"></script>
  <script src="//apps.bdimg.com/libs/jqueryui/1.10.4/jquery-ui.min.js"></script>
  <link rel="stylesheet" href="jqueryui/style.css">
  <script>
  $(function() {
    $( "#slider" ).slider({
      value:0,
      min: -3,
      max: +3,
      step: 0.01,
      slide: function( event, ui ) {
        $( "#amount" ).val( "$" + ui.value );
      }
    });
    $( "#amount" ).val( "$" + $( "#slider" ).slider( "value" ) );
  });
  </script>
</head>
<body>
 
<p>
  <label for="amount">捐款金额（$50 增量）：</label>
  <input type="text" id="amount" style="border:0; color:#f6931f; font-weight:bold;">
</p>
 
<div id="slider"></div>
 
 
</body>
</html>